Double deck continuous kiln



Dec. 17, 1940.

F. W. BROOKE DOUBLE DECK CONTINUOUS KILN Filed Feb. '28, 1959 3Sheets-Sheet l BY q E. if

ATTORNEY Dec. 17, 194-0. F. w. BROOKE 2.2249

DOUBLE DECK CONTINUOUS KILN Filed Feb. 28, 1959 3 Sheets-Sheet 5 F rtORNEY ATT Patented Dec. 17, 1940 PATENT OFFICE DOUBLE DECK CONTINUOUSKILN Frank W. Brooke, Pittsburgh, Pa., assignor to Swindell-DresslerCorporation, Pittsburgh, Pa., a corporation of Pennsylvania ApplicationFebruary 28, 1939, Serial No. 258,893

12 Claims.

The present invention relates to continuous tunnel kilns of a knowndouble deck type, in which the goods treated are inserted in the kilnchamber at one end and are moved through the kiln at one level, and arethen moved back through the kiln chamber at a different level. Foridentification purposes, the above mentioned kiln end may be referred toas the goods receiving and discharge end, and the opposite end may bereferred to as the level shift end of the kiln.

Ordinarily, such 'a kiln is heated by heating elements, which may beelectric resistors or combustion chambers of known form, and which arelocated only in the portion of the kiln adjacent its level shiftend,.the incoming goods being preheated in the remainder of the kiln, byheat transferred to them from the outgoing goods, which are therebycooled. In consequence, the highest kiln temperatures are attained insuch a kiln at, or adjacent, its level shift end.

While the goods may be moved through such a kiln in various ways, it isgenerally essential that mechanism should be provided at the level shiftend of the kiln, to transfer bodies, which in some cases may be ingotsor otherparts subjected to heat treatment in the kiln but usually aresupports for the goods treated in the form of kiln cars, boxes, ortrays, successively approaching the level shift end of the kiln chamber,from the approach level to the return level, and the primary object ofthe present invention is to provide simple and effective mechanismWithin the kiln chamber for transferring goods supports or other bodiesfrom one of said levels to the other.

A preferred form of the present invention, hereinafter described indetail, was devised for use in a kiln, m which goods supporting trays orboxes are moved in a known manner through the kiln chamber ineachdirection on a corresponding set of conveyor rolls which extendacross the kiln chamber at the proper level, and have their endsjouralled in the kiln walls. Ordinarily, such conveyor rolls are notidle rolls over which the work is pushed or pulled, but are rotated toadvance the work supports, as by means of a sprocket chain orreciprocating pawls, respectively engaging sprocket wheels orratchetwheels carried by the rolls.

My improved goods level shifting mechanism is characterized by itssimple and effective construction and operation, and by its adaptabilityfor use under relatively high temperatures, which in some cases, are butlittle below that at which mechanism parts made of any metal'practicallyavailable for use in the construction of the level shiftingmechanismwill fail. In its preferred form said mechanism comprises a transfertable or platform having a plurality of free running, or idler, rolls,and table supporting and operating means comprising arms each so pivotedat one end to the table and at its opposite end to turn about astationary axis extending transversely of the kiln, that said arms forma parallel motion linkage for holding the table horizontal whileswinging it back and forth between one position in which its rolls areat the level of the upper set of conveyor rolls, and a second level inwhich the table rolls are at a level of the lower set of conveyor rolls.

Another main object of the invention is to provide improved means formoving the goods off the transfer table and on to the return set ofconveyor rolls.

A further important object of the invention is to provide 'simple andeffective means for automatically effecting the intermittent movementsof the table between its different levels, and the intermittentoperation of the means for moving the goods or wares from the table ontothe return conveyor rolls, and suitably relating said movements andoperations to one another and to the movements of the goods supportslongitudinally of the kiln.

The various features of novelty which characterize my invention arepointed out with particularity in the claims'annexed to and forming apart of this specification. For a better understanding of the invention,however, its advantages, and specific objects attained with its use,reference should be had to the accompanying drawings and descriptivematter in which I have illustrated and described a preferred embodimentof the invention.

Of the drawings:

Fig. 1 is a diagrammatic side elevation of a continuous tunnel kiln,partly broken away and in section;

Fig. 2 is a transverse section on the line 22 of Fig. 3;

Fig. 3 is an elevation of a level shift end portion of the kiln, insection on the line 33 of Fig. 2;

Fig. 4 is a side elevation illustrating a detail of construction; and

Fig. 5 is a diagram illustrating an automatic control system for themotors operating transfer table and the means for moving goods off the atable.

In the drawings, I have illustrated the use of my invention in a kiln Ain which goods are moved through the kilnchamber from the goodsreceiving and discharging end of the chamber on an upper set of conveyorrolls B, and are then moved back from the level shift end of the kiln ona lower set of conveyor rolls b. The rolls of each set extendtransversely to the kiln chamber, and have their ends journalled at theopposite sides of the chamber. As shown the rolls B and b are eachformed with two tray guiding flanges, B and b, respectively, oneadjacent each side wall of the kiln chamber, and spaced apart by adistance equal to the width of trays or boxes C, which support the goodsmoved through the kiln.

As shown in Fig. 1, the upper set of rolls B,

extends out of the kiln chamber at its goods receiving and dischargingend, to provide a convenient loading platform on which the trays orboxes C may readily be placed in proper spaced relation. As shown, theset of lower rolls 1) similarly extends out of the kiln chamber at itsgoods receiving and discharging end, into end to end relation with areceiving table or platform comprising rolls D onto which the rolls bdischarge the boxes or trays C. The platform rolls D are not driven butare free to turn as the work supports C are moved onto the rolls D bythe conveyor rolls b, and are moved on? the rolls D by an attendantremoving goods from the kiln. The upper and lower sets of conveyor rollsB and b do not extend to the level shift end of the kiln chamber, butterminate at greater and lesser distances, respectively, therefrom, topermit the transfer table E to be positioned as hereinafter described.

The transfer table E is adapted to receive trays C, one at a time fromthe conveyor rolls and comprises a rigid grid like frame nearly as wideas the kiln chamber and slightly shorter than a goods support C, andcomprises side bar portions connected by transverse bars e. The table Eis movable between an uppertray receiving and lower tray deliveringposition at the levels of the rolls B and b, respectively, which areshown in Fig. 3, in full and dotted lines, respectively. The table Ecomprises free running rolls E, which are parallel to the conveyor rollsB and b and are journalled at their ends in the table frame, and whichare suitably displaced from one another longitudinally of the kiln, toproperly support a tray or box C not only during the level shiftingoperation, but also when a tray or box is being moved on to and off ofthe table.

The table E is supported, and given its movements, by a pair of arms Eand a second pair of arms E The two arms E are located at opposite sidesof the kiln chamber and each is secured at one end to a correspondingrock shaft E extending through the adjacent side wall of the kiln. Theend of each arm E remote from the corresponding shaft E is pivotallconnected to the frame of the table E adjacent the end of the latterwhich is nearest to the level shift end of the kiln. The two arms E oneat each side of the kiln chamber, are each mounted at one end on acorresponding shaft E extending through the adjacent side wall of thekiln chamber so as to turn about the axis of said shaft, and each ispivotally connected to the frame of the table E adjacent the end of thelatter which is nearest to the goods receiving and discharge end of thekiln chamber. The distance between the axis of its pivotal connectionwith the table and the axis of the shaft E or E on which it is mounted.is the same for each of the arms E and E Those axes are so relatedmoreover, that rotative movements imparted to the crank shafts Eexternal end of each of the shafts E and in mesh with a spur gear Fsecured to the corresponding end of a horizontal shaft F which extendsthrough the kiln structure at a level below that of the rolls b. Asshown, the spur gear F" at one side of the kiln is in mesh with thedriving element G of a speed reducing gear G, which has its drivingshaft coupled to the shaft of a reversible motor M adapted on itsrotation alternately in opposite directions to move the table E back andforth between its upper and lower positions shown in full and dottedlines in Fig. 3.

When the table E is in its lower position, a go s suppor g, then on thetable, may be pushed off the t le and on to the rolls 2), by a ram orpusher bar which extends longitudinally of the kiln thro gh the end wallof the kiln chamber, and has itsouter end connected to a cross head Imounted in a guideway I for movement in the longitudinal direction ofthe ram and kiln. The means shown for giving the ram I its longitudinalmovements, include a lever J having its lower end journalled on astationary fulcrum pivot J. The lever J is oscillated to advance andretract the arm by means of a crank shaft K parallel to and above thepivot J, and carrying a crank arm K pivotally connected at its free endto a cross head K working in a longitudinal slot or guideway J in thelever J. The crank shaft K as shown forms the output or driven shaft ofa speed reducing gear K which is driven by an intermittently operatingmotor L.

In the contemplated operation of the apparatus shown in the drawings, assoon as a work support C is moved into a predetermined suitablycentered, position on the table E, then in its upper position, the motorM is set into operation to lower the table. Such operation of the motorM is interrupted when the table reaches its lowermost dotted lineposition, and the motor L is then operated to effect one completerotation of the crank shaft K, and thereby move the lever J from thefull line position into the dotted line position, and thence back intofull line position shown in Fig. 3. As the lever J moves from its fullline position into its dotted line position, the plunger I is advancedsufficiently to push a goods support C, initially on the table E, offthe latter, and on to the rolls 2). After the plunger readiness toreceive the goods support C then at I the head of the train of suchsupports being advanced by the rolls B.

With the lever J and its operating connections arranged as shown, ittakes only about half as long to move the lever J from its dotted lineposition to its full line position as is required for the reversemovement. Furthermore, the ratio of longitudinal movement of the ram Ito the angular movement of the crank shaft K, is much smaller during theinitial and final portions than during the intermediate portions of themovement of the ram while in operative engagement counterweight? outsideof'the kiln-chamber. The shaft P, arm P" and counterweight P are soproportioned and arranged that during all but the final portion of, themovement of a work support C onto the elevated table E, the arm P willbe held by the counterweight P in the generally upright position shownin Fig. 3 in dotted lines, at the left of the full line showing of thearm. As a tray which is being moved on to the table E, approaches theend of such movement, it engages thearml? and moves it out of its dottedline position'and into the position shown in Fig. 3. The movement of thearm P into said full line position is utilized to start the series ofmotor operations which result in the lowering of the table E, theoperation of the ram I to transfer the work support on the table fromthe latter onto the conveyor rolls b, and the return of the table E toits upper position. 1 i

In the control system form illustrated diagrammatically in Fig. 5, themotor M is energized for operation in the direction to lower the table Eby the movement of a switch Q into engagement with a switch contact q,whereby a motor'energizing circuit including a field winding M isoperatively connected to supply electric conductors I and 2. The motor Mis energized for operation in the reverse direction by the movement of aswitch R into engagement with a contact r, whereupon a second motorenergizing circuit including a field winding M is operatively connectedto the supply conductors I and 2. As shown in Fig. 5, the motor L isenergized for operation in the one direction in which that motoroperates, by the adjustment of a switch S into engagement with a contacts, whereby an energizing circuit for the motor L including its fieldwinding L is operatively connected between the supply conductors l and2.

As diagrammatically shown in Fig. 5, each of the switches Q, R and S ismoved into its motor energizing position by electromagnetic meanscomprising coils t, 1m and w, respectively. As diagrammatically shown,each of the switches Q and R, is moved out of its motor energizingposition by mechanical means comprising a cam rotated on and inaccordance with changes in the position of the table E, or, asdiagrammatically shown, in direct accordance with the correspondingmovements of the motor M. The switch 5' is moved to deenergizethe'motorL, by electromagnetic means including a coil m. For the purposes of-thesystem diagrammatically illustrated, each of the switches Q,-R and S,and also the switch W provided for sequence control purposes hereafterset forth, is unbiased and tends to remain in any position into which itis adjusted until positively moved into a different position.

As diagrammatically illustrated in Fig. 5, a bridging contact Umechanically connected to the rock shaft P is moved into bridgingrelation with a pairof contacts T when the arm P is moved by a worksupport into its fullline position shown in Fig. 3. When the contacts Tare thus connected, theycomplete an energizing circuit connectionbetween the conductors l and 2 for the coil t, the energization of whichmoves the switchQ into engagement with the switch contact q, and therebystarts the motor M into operation in the direction to lower the table E.Y i

The energizing circuit forthe coil It also includes a switch actuatingcoil ta, and apair of contacts rf which are connected by a bridgingcontact ra carried by the switch R, when the circuit is energized asabove described. The contacts r are not connected by the bridgingcontact m, and the coil t is not energized by movement of the contact Uinto bridging relation with the contacts T, during the subsequent tableelevating operation, as the switch R then holds its contact ra out ofengagement with the contacts r.

On the energization of the coil ta, the latter moves the switch W intothe position shown in Fig. 5, in which it forms a bridge connectingcontact wa. The bridging of the contacts wo has no immediate result, butis a control circuit preparing action, essential to the energization ofthe motor L which occurs when the continuing operation of the motor Moperates the cam M to shift the switch Q from the position shown in Fig.into its other operative position, in which an insulated contact partqa, carried by the switch, forms a bridging connection between contactsq. The bridging of the contacts q closes a control circuit connectionbetween supplyconductors I' and2, whichincludes the contacts wa, thecontacts q, and the coil 10. The latter, when energized, moves theswitch S into engagement with the contacts s, and thus starts the motorL into operation which continues until the crank shaft K is given onecomplete revolution and one complete revolution is thereby given to abridging contact Y which is shown in Fig. 5 as carried by an arm securedto the shaft K.

In its initial and final position shown in Fig. 5, the contact Y forms abridging connection between two contacts X. In some intermediate portionof its turning movement, the contact Y forms a bridging connectionbetween two contacts Z, and thereby momentarily energizes a controlcircuit connection between sup-ply conductors l and 2 which includes acoil 2 thereby energized to shift the switch W out of engagement withthe contacts um and into bridging engagement with contacts wb, andthereby prepare a control circuit for energization. on the subsequentreturn of the contact Y into position shown in Fig. 5. The lastmentioned control circuit r includes switch actuating coils :c and 02a.

The energization of the coil as moves the switch S out of engagementwith the contact 8, and thereby deenergizes the motor L, and theenergization of the coil rm shifts the switch R into engagement with thecontact r, and thereby en ergizes the motor M for operation in thedirection to raise the table E from its dotted line position into itsfull line position shown in Fig. 3. As the table moves into its lastmentioned position, the cam 1W moves the switch R out of engagement withthe contact 1' and thus terminates the series of control actionsinitiated by the movement of the arm P from its left hand dotted lineposition into the full line position shown in Fig. 3.

While in'accordance with the provisions of the statutes, I haveillustrated and described the best form of embodiment of my inventionnow known to me, it will be apparent to those skilled in the art thatchanges may be made in the form of the apparatus disclosed withoutdeparting from the spirit of my invention as set forth in the appendedclaims and that in some cases certain features of my invention may beused to advantage without a corresponding use of other features. 1

Having now described my invention, what I with the Work. In consequence,the'operative and return movements of the lever J may be effected in adesirably short period of time, without accelerating or decelerating themovement of the work support operated on, rapidly enough to subject thework to a significant jar or shock, when the work support is initiallyengaged by the ram, or in the event that the work support engaged by theram is moved by the latter into engagement with the rear goods supportof the train of goods supports moving to the goods receiving anddischarge end of the kiln.

Ordinarily, however, I prefer to avoid movement of a work support Cengaged by the ram 1, into engagement with the adjacent work support onthe conveyor rolls b by making the speed at which the rolls 1) advancethe work supports slightly, for example, one percent, higher than thespeed at which the work supports are advanced by the rolls B. Thisresult may be secured of course, by making the angular speed of therolls 1) slightly higher than that of the rolls B, when the rolls areall of the same diameter, or, when the rolls are driven at the sameangular speeds, as is ordinarily desirable, the rolls b may be made oneper cent, or so, larger in diameter than the rolls B.

To prevent the lower set of rolls 1) from offering objectionablefrictional resistance to the movement of the supports C off the table Eand on to said rolls, such of the. latter, four as shown. as may beengaged by a support C which is being advanced by the ram I, are free tooverrun, or turn freely at a velocity greater than that at which theyare turned by the normal conveyor roll rotating means. Said rolls may begiven their overrunning capacity in various known ways. Thus, forexample, each of the four rolls b closest to the level shift end of thekiln, may have its driving wheel N journalled on the roll and bearranged to drive the latter, as shown in Fig. 4, through pawls Ncarried by the wheel M and engaging a ratchet wheel N secured to theroll. Each of the four overrunning rolls provided with parts N, N and Nis thus free to revolve with an angular velocity greater than that ofthe driving wheel N mounted on it.

Advantageously, and as is shown in Fig. 3, when the table E is in itsupper position the axes of the pivotal connections between the table andthe links E and E are slightly to the rear of the axes of the shafts Eand E respectively. In consequence, the initial portion of the normalmovement of the table E away from its upper position includes a smallvertical upwardly directed component. This is not only adapted tonullify any possible tendency of the support '0 on the table E to adhereto and drag forward the support C immediately to its rear, but alsotends to eliminate risk of having the table E moved out of its normalfull line position as a result of frictional resistance to movement overthe table of a support C which is being moved onto the table by the.rolls B. With the described arrangement, such tendency to objectionablemovement of the table E is opposed by gravitational forces which tend toturn the arms E and E counterclockwise as seen in Fig. 3 from theirupper position. As will be apparent, the described arrangement makes itreadily possible to provide the side walls of the in with stopspositively preventing movement of the table E to the left of its fullline position show in Fig. 3.

As previously indicated, the present invention is not concerned with theform or character of the kiln heating means employed. On the contrary,an advantage characteristic of the invention isthat it does notinterfere with the use of any form of heating means customarily employedin heating kilns of the character shown. As shown in the drawings, thekiln is heated by means of a plurality of heating elements 0', each inthe form of a tubular combustion chamber of known type. As shown,elements 0 are distributed beneath the conveyorrolls b along a portionof the kiln extending away from its level shift and for a distance whichmay be forty per cent, or so, of the length of the kiln, and otherelements 0 are distributed along a portion of the kiln above the pathwayfor the goods on the rolls B adjacent the level shift end of the kilnand shorter than the portion including the lower elements 0. To providespace for the upper elements 0 and for a desirable convectioncirculation of the atmosphere in the high temperature portion of thekiln, the vertical depth of the kiln chamber is greater in the portionthereof including the heating elements 0, in the remainder of the kiln.The character of the transfer table E and its operating mechanism is notonly such as to avoid interference with the convection currentcirculation of the kiln atmosphere, which is especially important in akiln of the type shown, but is such that when the table is in its lowerposition, desirable access to the portion of the goods pathway above therolls b, as well as to the portion above the rolls B, is made possibleby providing a normally closed, but easily opened, doorway A, in thelevel shift end wall of the kiln. Such access to the high temperatureend portion of the kiln, is especially important because of theaccidental jamming of goods supports and other accidents, which mayoccur from time to time in that portion of the kiln.

To automatically start and stop the motors M and L as required for thepreviously mentioned normal mode of operation, I have devised anautomatic control system, which ineludes means responsive to andoperative on the movement of a carrier C into a predetermined positionon the table E to start the motor M into operation in the direction tolower the table E, and includes means for stopping the motor M andstarting the motor L on the movement of the table E into its lowerposition, and includes means automatically actuated on the movement ofthe table E into its lowermost position, to stop the motor M and startthe motor L, and includes means automatically actuated on the completionof one revolution of the crank shaft K to interrupt the operation of themotor L and to start the motor M into operation in the direction to movethe table E back into its upper position, and includes meansautomatically actuated on the movement of the table E into its upperposition to interrupt the operation of the motor M. v

The described control system may take various forms, one of which isdiagrammatically illustrated by way of example in Fig. 5, and includesmeans shown in Figs. 2 and 3, which is responsive to the movement of acarrier C into a predetermined position on to the table E. The lastmentioned means includes a rock shaft P extending across the kilnstructure below the level of the bottom of the table E, when the latteris in its lowermost position. The shaft 1? has secured to it an arm Pwithin the kiln chamber, and a .setof conveyor rolls extending acrossthe kiln chamber atintervals along the lengthof the latclaim as new anddesire tosecure byLetters Patent, is:

1. A double deck'continuous tunnel kiln, .comprising in combination, anelongated kiln chamber, and means for moving goods through the kilnchamber from oneend thereof to the other and thence back to the firstmentioned end of the kiln chamber, comprising upper and lower trackwaysalong one of which goods are moved in one direction and along the otherof which the goods are moved in the return direction, said lowertrackway extending past said upper trackway at said other end of thekiln, a transfer table,

and means for moving said table in parallelism I with itself alonga pathcurved about an axis transverse to the length of the kiln chamberbetween an upper position in which the table forms an extension of theupper trackway and a lower position in which the table forms anextension of the lower trackway.

2. A kiln as specified in claim 1 comprising means, separate from themeans for moving goods through the kiln along said trackwavs, andadapted to move the goods off the transfer table and on to the trackwayalong which the goods are moved back to the end of the kiln remote fromthe table.

3. A kiln as specified in claim 1, including a power mechanism formoving the transfer table, means actuated by goods moving on to thetransfer table, when the latter is in the position in which it forms anextension of the trackway along which goods are moved toward the end ofthe kiln at which the table is located, to set said mechanism intooperation to move the transfer table into the position to which it formsan extension of the trackway on which goods are moved away from thetransfer table, power means automatically set into operation on themovement of the table into its last mentioned position, to move goodsoff the table and on to the last mentioned trackway and meansautomatically actuated after a predetermined extent of operation of saidpower means to interrupt the operation of the latter and to set' saidmechanism into operation toreturn said table to its goods receivingposition.

4. Akiln as specified in claim 1, including means adapted to move goodsoff the transfer table and on to the trackway along which the goods aremoved away from the table, comprising a lever ivoted at one end tooscillate about a stationary axis, a goods engaging device operativelyconnected to the other end of the lever, a crank arm revolving about anaxis parallel to the first mentioned axis and a pivotal connectionbetween the said crank arm and lever slidable along an intermediateportion of the length of the latter and through which said device ismoved in the direction to move goods off the table and is moved in theopposite direction during greater and lesser portions, respectively, ofeach rotation of the crank shaft.

5. A tunnel kiln as specified in claim 1, in which each trackway isformed by conveyor rolls extending across the kiln chamber anddistributed longitudinally thereof, and in which the transfer tablecomprises free running rolls extending transversely of the kiln chamberand having their upper edges at the same level as the upper edges of theupper trackway conveyor rolls or the lower trackway conveyor rolls,accordingly as the table is in its upper or lower position.

6. A continuous tunnel kiln as specified in claim 1, in which each goodstrackway comprises a ter, and in which the return trackway conveyor,rolls immediately, adjacentthe transfer table are adapted to turn;freely in the direction in which goodsbeing moved off the transfertable tend to turn. the iastmentioned conveyor rolls, and

comprising means for positively rotating the last mentioned rolls andthe other rolls of the same set in the direction to move the goods tothe end of the kiln chamber remote from the transfer table. r

7. A double deck continuous tunnel kiln,,comprising in combination, anelongated kiln chamber, and means for moving goods through the kilnchamber from one end thereof to the other and thence back to the firstmentioned end of the kiln chamber, comprising a lower trackway alongwhich the goods are moved in one direction and an upper trackway alongwhich the goods are moved in the return direction, said lower trackwayextending past said upper trackway at said other end of the kiln and atransfer table, and parallel motion table supporting means comprisingarms pivoted to turn about stationary horizontal axes extendingtransversely to and displaced from one another longitudinally of thekiln and connected to said table to turn relatively thereto aboutsimilarly displaced horizontal axes from one another, and adapted toswing said table between an upper position in which the table forms anextension of the upper'track- Way and a lower position in which it formsan extension of the lower trackway.

8. A double deck continuous tunnel kiln, comprising in combination, anelongated kiln chamber, a goods trackway in said chamber extending fromone end thereof into proximityvwith the other chamber end but separatedfrom the latter by a relatively short distance, a second goods trackwayat a level above that of the first men tioned trackway extending alongsaid kiln chamber from said one end thereof into proximity with theother chamber end but separated from the latter by a distance somewhatgreater than the first mentioned distance, a transfer table in said kilnchamber, and means for swinging said table between an upper position inwhich it forms an extension of the upper trackway and a lower positionin which it forms an extension of the lower trackway.

9. A tunnel kiln as specified in claim 8 in which said kiln is formed atits end at which the transfer table is locatedwith an end wall formedwith a normally closed doorway adapted to be opened to provide access tothe kiln chamber. Y

10. A kiln as specified in claim 8, including kiln heating elementsadjacent the end of the kilnchamber at which the transfer table islocated above the upper and below the lower of the two tr-ackways'.

11. A kiln as specified in claim 1, in which the means for moving thetransfer table between its upper and lower positions comprises ahorizontal rock shaft extending transversely of the kiln chamber andhaving arms secured to it at opposite sides of the chamber and eachpivotally connected at its free end to said table, and other arms, eachpivoted to turnabout a corresponding axis parallel to and at thesame'level as said rock shaft, but displaced from the latter in thedirection of the length of the kiln and each connected to the table by apivotal connection at the same level as the pivotal connections betweenthe first mentioned arms and the table and displaced therefrom in thesame direction and to the same extent as the said corresponding axis isdisplaced from said rock shaft.

12. A kiln as specified in claim 1 inwhich goods are moved along theupper and lower 'trackways respectively toward and away from the end ofthe kiln at which the transfer table is located ,and in which an armpivoted to turn about an axis transverse to the kiln and adjacent the 10lower trackway level, extends between the table and the adjacent end ofthe'kiln in position to be engaged and given a movement away from thetable by goods moved on to the table from the last mentioned trackway,and including power mechanism for moving the table from its upperposition to its lower position set into operation by the said movementof said arm away from the table.

FRANK W. BROOKE.

